Jenkins T G, Ford J J, Klindt J
Roman L. Hruska U.S. Meat Animal Research Center, U.S. Department of Agriculture, Clay Center, NE 68933.
J Anim Sci. 1988 May;66(5):1179-85. doi: 10.2527/jas1988.6651179x.
Data were collected from intact males, castrated males and ewe lambs to investigate the effect of presence or absence of testosterone prenatally and during the postweaning period on postweaning growth, feed intake and carcass chemical composition. Half the lambs from each sex were the progeny of dams that had received five injections of testosterone cyprionate from d 32 through d 87 of gestation. Linear contrasts were used to detect differences. Postweaning daily gain of intact males was greater (P less than .01) than that of male castrates. Ewe lambs from treated dams had approximately 12% greater rate of growth (P less than .04) than ewe lambs from control dams. Ewe lambs from dams that had been treated were 28% more efficient (P less than .01) in the conversion of food to weight than those from untreated dams. Ewe lambs from treated dams had heavier livers (P less than .07). Carcass protein for intact males was greater (P less than .11) than for castrates, and extractable fat was less (P less than .05). Masculinization of growth characteristics of ewe lambs affected the quantity of carcass fat relative to control ewes (7.59 vs 8.92 kg). These ewe lambs also had more water in the carcass than did the control ewes (13.93 vs 12.29 kg). Administration of exogenous testosterone to pregnant ewes over an interval of time approximating time of sexual differentiation in the fetus enhances postweaning growth rate, feed conversion efficiency and chemical composition of genetic females.
收集了完整雄性、去势雄性和母羊羔的数据，以研究产前和断奶后阶段睾酮的有无对断奶后生长、采食量和胴体化学成分的影响。每种性别的羊羔中，一半是其母羊在妊娠第32天至第87天接受了五次环丙孕酮睾酮注射的后代。使用线性对比来检测差异。完整雄性断奶后的日增重比去势雄性更大（P小于0.01）。来自接受处理母羊的母羊羔比来自对照母羊的母羊羔生长速度快约12%（P小于0.04）。来自接受处理母羊的母羊羔在食物转化为体重方面比未处理母羊的母羊羔效率高28%（P小于0.01）。来自接受处理母羊的母羊羔肝脏更重（P小于0.07）。完整雄性的胴体蛋白质比去势雄性更多（P小于0.11），可提取脂肪更少（P小于0.05）。母羊羔生长特征的雄性化影响了相对于对照母羊的胴体脂肪量（7.59对8.92千克）。这些母羊羔胴体中的水分也比对照母羊更多（13.93对12.29千克）。在接近胎儿性别分化时间的一段时间内，给怀孕母羊施用外源性睾酮可提高遗传雌性的断奶后生长速度、饲料转化效率和化学成分。
